The MAX4990 high-voltage DC-AC converter is ideal for driving electroluminescent (EL) lamps. The MAX4990 features a wide +2.4V to +5.5V input range that allows the device to accept a wide variety of voltage sources such as single-cell lithium-ion (Li+) batteries and higher voltage battery chargers. The lamp outputs of the device generate up to 250V peak-to-peak output voltage for maximum lamp brightness.
The MAX4990 utilizes an inductor-based boost converter to generate the high voltage necessary to drive an EL lamp. The boost-converter switching frequency is set with the combination of an external capacitor connected from SW to GND and an external resistor connected from SLEW to GND.
The MAX4990 uses a high-voltage full-bridge output stage to convert the high voltage generated by the boost converter to an AC waveform suitable for driving the EL panel. The EL output switching frequency is set with the combination of an external capacitor connected from EL to GND and an external resistor connected from SLEW to GND.
The MAX4990 uses a proprietary acoustic noise-reduction circuit that controls the slew rate of the AC voltage, reducing audible noise from the EL panel. The slew rate is set with an external resistor connected from SLEW to GND.
The MAX4990 features an EL lamp dimming control (DIM) that allows the user to set the EL output voltage with a PWM signal, a DC analog voltage, or a resistor connected from the DIM input to GND. A capacitor placed in parallel to the resistor on DIM allows the user to program a slow turn-on/-off time that generates a soft fade on/fade-off effect of the EL lamp.
The MAX4990 enters a low-power shutdown mode (100nA max) when the EN and DIM inputs are connected to GND. The MAX4990 also enters thermal shutdown if the die temperature rises above +158°C.
The MAX4990 is available in a space-saving, 14-pin, 3mm x 3mm TDFN package and is specified over the extended -40°C to +85°C operating temperature range.
Key Features
Applications/Uses
ESD-Protected EL Lamp Outputs
±15kV Human Body Model
±4kV IEC 61000-4-2 Contact Discharge
±15kV IEC 61000-4-2 Air-Gap Discharge
250VP-P (MAX) Output for Highest Brightness
Wide +2.4V to +5.5V Input Voltage Range
Resistor-Adjustable Slew-Rate Control for Audible Noise Reduction
Externally Driven Lamp and Switching Converter Frequencies
Capacitor-Adjustable Lamp and Switching Converter Frequencies
Low 100nA Shutdown Current
DIM Input for Controlling Output Voltage Through DC Analog Voltage, PWM, or Resistor to GND
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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